22. The tolerances for the form work of columns and beams range from
A. -3 mm to + 6 mm
B. - 4 mm to + 8 mm
C. - 6 mm to + 12 mm
D. - 8 mm to + 12 mm.
23. If the specified thickness of a footing is 100 cm, the depth of the form work may be tolerated from
A. - 2 mm to + 2 mm
B. - 3 mm to + 3 mm
C. - 4 mm to + 4 mm
D. - 5 mm to + 5 inm.
24. Removal of props under
A. slabs spanning upto 4.5 m is 7 days
B. slabs spanning upto 4.5 m is 14 days
C. beams spanning upto 6 m is 14 days
D. all the above.
25. The cover to the main reinforced may be reduced up to one third of the specified cover but not less than
A. 5 mm
B. 7 mm
C. 10 mm
D. 15 mm.
26. Moist curing of the exposed surfaces of concrete is done at least for
A. 3 days
B. 5 days
C. 7 days
D. 14 days.
27. For under water concreting.
A. at least 10 percent more cement is required as compared to dry conditions
B. the volume of coarse aggregates shall not be less than one and half times and not more than twice that of fine aggregate
C. the slump should not be less than 100 mm and not more than 180 mm
D. All the above
28. The grade of plain concrete to be used in sea water or structures exposed to sea water, should be
A. M 10
B. M 15
C. M 20
D. M 30.
Page 4 of 21